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CN-121975532-A - Functional biochar for saline-alkali soil remediation, soil conditioner prepared from functional biochar and preparation method of functional biochar

CN121975532ACN 121975532 ACN121975532 ACN 121975532ACN-121975532-A

Abstract

The invention discloses functional biochar for saline-alkali soil remediation, a soil conditioner prepared from the functional biochar and a preparation method of the soil conditioner, and belongs to the technical field of soil conditioner preparation. The soil conditioner for saline-alkali soil remediation comprises, by weight, 40-50 parts of functional biochar, 35-43 parts of humic acid, 2-6 parts of citric acid and 6-12 parts of organic conditioning agent, wherein the functional biochar is prepared by combining 3,3' -dihydroxybenzidine and chitosan on the surface of the biochar by taking formaldehyde as a cross-linking agent. The soil conditioner prepared by adopting the substances has excellent effect of repairing saline-alkali soil.

Inventors

  • YU BIN
  • PAN YUAN
  • LU CHENGHAO

Assignees

  • 上海鸣桦环境科技有限公司

Dates

Publication Date
20260505
Application Date
20260403

Claims (10)

  1. 1. A soil conditioner for preparing functional biochar for saline-alkali soil remediation is characterized by comprising, by weight, 40-50 parts of functional biochar, 35-43 parts of humic acid, 2-6 parts of citric acid and 6-12 parts of organic conditioner, wherein the functional biochar is prepared by combining 3,3' -dihydroxybenzidine and chitosan on the surface of the biochar by taking formaldehyde as a cross-linking agent.
  2. 2. The soil conditioner according to claim 1, wherein the method for preparing the functional biochar comprises the steps of: q1, preparing straw biochar by an oxygen-limited pyrolysis method; and Q2, adding chitosan into glacial acetic acid water solution, sequentially adding straw biochar, 3' -dihydroxybenzidine and ethylenediamine, stirring and mixing, dropwise adding formaldehyde, stirring, adding sodium hydroxide solution, suction filtering, washing, drying and grinding to obtain the functional biochar.
  3. 3. The soil conditioner according to claim 2, wherein step Q1 comprises the steps of washing, drying, pulverizing, sieving the straw to obtain straw powder, adding the straw powder into a crucible, sealing, wrapping tinfoil, and calcining; washing with tap water, and then leaching with deionized water; The drying is at 80-83 ℃; the sieving is a nylon sieve with the diameter of 0.15 nm; the calcination is carried out by heating to 550-580 ℃ at a heating rate of 5 ℃ per min, and reacting for 2-4h at a heat preservation.
  4. 4. The soil conditioner according to claim 2, wherein in the step Q2, the ratio of chitosan, glacial acetic acid aqueous solution, straw biochar, 3' -dihydroxybenzidine, ethylenediamine and formaldehyde is (2-2.8) g (300-350) mL (10.2-16.8) g (20.23-24.85) g (5.88-6.24) g (9.2-10.6) mL.
  5. 5. The soil conditioner of claim 1, wherein the organic conditioner is prepared by a process comprising the steps of: S1, adding diisopropylamine into tetrahydrofuran, adding hexane containing n-butyllithium in an ice bath environment, stirring, cooling, adding tetrahydrofuran containing methyl isobutyrate and triethylchlorosilane, stirring at room temperature, rotary steaming, and distilling under reduced pressure to obtain colorless transparent liquid; And S2, adding acrylic acid into a sodium hydroxide solution, stirring uniformly, sequentially adding 2-acrylamido-2-methylpropanesulfonic acid and sodium lignin sulfonate, continuously stirring, then adding dichloromethane containing the colorless transparent liquid and deionized water containing corn starch, stirring and mixing, then adding ammonium persulfate and N, N' -methylenebisacrylamide, carrying out oil bath heating reaction, soaking, washing, freeze-drying and crushing after the reaction is finished, so as to obtain the organic conditioner.
  6. 6. The soil conditioner according to claim 5, wherein the ratio of diisopropylamine, n-butyllithium, hexane, methyl isobutyrate and triethylchlorosilane used in step S1 is (4.88-5.34) mL, (8.82-10.25) g, (20.12-22.28) mL, (3.12-3.76) mL, and (5.48-6.34) mL.
  7. 7. The soil conditioner according to claim 5, wherein in the step S2, the ratio of the amounts of acrylic acid, sodium hydroxide solution, 2-acrylamido-2-methylpropanesulfonic acid, sodium lignin sulfonate, colorless transparent liquid, methylene chloride, corn starch, deionized water, ammonium persulfate and N, N' -methylenebisacrylamide is （8.72-9.25）g：（18.88-22.12）mL：（2.85-3.22）g：（1.09-1.32）g：（0.92-1.24）mL：（6.82-7.34）mL：（1.22-1.86）g：（9.23-10.29）mL：（0.12-0.16）g：（0.013-0.019）g.
  8. 8. A method of preparing a soil conditioner according to any one of claims 1 to 7, comprising the steps of: spraying deionized water on the surface of the functional biochar, then spraying citric acid solution to adjust the pH, standing and aging to obtain pretreated functional biochar; Crushing humic acid, sieving, sequentially adding pretreated functional biochar and organic conditioner, uniformly mixing, spraying water, granulating, drying, and cooling to obtain the soil conditioner.
  9. 9. The method for preparing a soil conditioner according to claim 8, wherein in the first step, the concentration of the citric acid solution is 0.1g/mL, the pH is adjusted to be 6.0-7.0, and the standing aging time is 20-24 hours.
  10. 10. A functional biochar for saline-alkali soil remediation, characterized in that the functional biochar is prepared by a method comprising the steps of: q1, preparing straw biochar by an oxygen-limited pyrolysis method; and Q2, adding chitosan into glacial acetic acid water solution, sequentially adding straw biochar, 3' -dihydroxybenzidine and ethylenediamine, stirring and mixing, dropwise adding formaldehyde, stirring, adding sodium hydroxide solution, suction filtering, washing, drying and grinding to obtain the functional biochar.

Description

Functional biochar for saline-alkali soil remediation, soil conditioner prepared from functional biochar and preparation method of functional biochar Technical Field The invention belongs to the technical field of soil conditioner preparation, and particularly relates to functional biochar for saline-alkali soil remediation, a soil conditioner prepared from the functional biochar and a preparation method of the soil conditioner. Background The saline-alkali soil is used as a global ecological problem, and the high sodium ion concentration of the saline-alkali soil leads to soil structural disintegration, acceleration of mineralization of organic carbon and inhibition of microbial activity, and directly threatens sustainable development and ecological safety of agriculture. Although the traditional chemical modifier can replace sodium ions, the secondary pollution risk exists, and the problem of degradation of carbon sink function of soil cannot be solved. Biochar, as a carbon-rich porous material prepared by pyrolysis of biomass under oxygen-limited conditions, exhibits unique advantages in saline-alkali soil remediation due to its high specific surface area, strong adsorptivity and rich oxygen-containing functional groups. Research shows that the biochar can improve the stability of soil aggregate through pore structure recombination, adsorb sodium ions and replace calcium and magnesium ions by utilizing negative charges on the surface, and simultaneously enhance the fertilizer retention capacity by improving the cation exchange capacity. In addition, the durability of the biochar enables the biochar to be stored in soil for hundreds of years, and the long-term carbon fixation potential is remarkable. However, the original biochar has the limitations of high ash content, salinity inhibition and the like, and the targeted repair function of the original biochar needs to be improved by modification technologies such as acid dipping, co-composting or nanoparticle loading, so that an energy-assisting type biochar system with the capabilities of salinity regulation, nutrient maintenance and carbon sequestration is formed. The patent CN117801823A discloses a biomass charcoal and biological calcium type soil conditioner which can achieve both soil improvement and carbon sink, and comprises, by weight, 30-35 parts of biomass charcoal powder, 5-10 parts of wood vinegar, 30-35 parts of activated oyster shell powder, 5-10 parts of fulvic acid, 25-30 parts of soybean meal, 0.05-0.1 part of biological microbial inoculum and 5-10 parts of polyglutamic acid. By adding the soil conditioner at the position of 10-20cm of the saline-alkali soil, the alkaline soil, especially the alkaline soil with the pH value of more than 8, can be effectively improved, the soil environment can be improved, and the saline-alkali soil can be restored. Although the soil conditioner prepared by the method has a certain effect in the treatment of the saline-alkali soil, the alkaline soil with the pH value of more than 8 can be purposefully improved, and the practical application of the soil conditioner is still limited. For example, the synergistic action mechanism of each component in the modifier is not clear, the timeliness of nutrient release and salt adsorption is possibly not matched, the activity of the biological microbial inoculum is easily inhibited by an extreme saline-alkali environment to influence the long-term restoration effect, and meanwhile, the local excessive application of components such as oyster shell powder and the like can possibly cause the risk of soil hardening and limit the deep penetration capacity of the heavy salinized soil, so that the application of the biological microbial inoculum is limited. Disclosure of Invention The invention aims to provide functional biochar for saline-alkali soil restoration, a soil conditioner prepared from the functional biochar and a preparation method of the functional biochar, and aims to solve the technical problem that the soil conditioner in the prior art is poor in restoration capacity of saline-alkali soil. In order to achieve the above purpose, the present invention adopts the following technical scheme: the invention provides a soil conditioner for preparing functional biochar for saline-alkali soil remediation, which comprises, by weight, 40-50 parts of functional biochar, 35-43 parts of humic acid, 2-6 parts of citric acid and 6-12 parts of organic conditioning agent, wherein the functional biochar is prepared by combining 3,3' -dihydroxybenzidine and chitosan on the surface of the biochar by using formaldehyde as a cross-linking agent. As one embodiment, the method for preparing the functional biochar comprises the following steps: q1, preparing straw biochar by an oxygen-limited pyrolysis method; and Q2, adding chitosan into glacial acetic acid water solution, sequentially adding straw biochar, 3' -dihydroxybenzidine and ethylenediamine, stirring and mixing, dropwise a